Theodor Schwann was a
GermanGermany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
physiologistPhysiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
. His many contributions to
biologyBiology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
include the development of
cell theoryCell theory refers to the idea that cells are the basic unit of structure in every living thing. Development of this theory during the mid 17th century was made possible by advances in microscopy. This theory is one of the foundations of biology...
, the discovery of
Schwann cellSchwann cells or neurolemmocytes are the principal glia of the peripheral nervous system . Glial cells function to support neurons and in the PNS, also include satellite cells, olfactory ensheathing cells, enteric glia and glia that reside at sensory nerve endings, such as the Pacinian corpuscle...
s in the
peripheral nervous systemThe peripheral nervous system consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system to the limbs and organs. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain...
, the discovery and study of
pepsinPepsin is an enzyme whose precursor form is released by the chief cells in the stomach and that degrades food proteins into peptides. It was discovered in 1836 by Theodor Schwann who also coined its name from the Greek word pepsis, meaning digestion...
, the discovery of the organic nature of
yeastYeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
, and the invention of the term
metabolismMetabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
.
Theory
His generalization became the foundation of modern histology, and in the hands of
Rudolf VirchowRudolph Carl Virchow was a German doctor, anthropologist, pathologist, prehistorian, biologist and politician, known for his advancement of public health...
(whose cellular pathology was an inevitable deduction from Schwann) placed modern
pathologyPathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
on a truly scientific basis knowledge. After studying medicine in Berlin, Schwann assisted the physiologist Johannes Peter Müller (1834–38). In 1836, while investigating digestive processes, he isolated a substance responsible for digestion in the stomach and named it pepsin, the first enzyme prepared from animal tissue. While professor of physiology at the Catholic University of Leuven (Louvain), Belg. (1839–48), he observed the formation of yeast spores and concluded that the fermentation of sugar and starch was the result of life processes. He knew Mathias Schleiden well, and a year after the latter, working at University of Jena, advanced the cell theory for plants, Schwann extended it to animals in his Microscopical Researches into the Accordance in the Structure and Growth of Animals and Plants (1839).
At the universities of Leuven and Liège, in Belgium (1849–79), he also investigated muscular contraction and nerve structure, discovering the striated muscle in the upper esophagus and the myelin sheath covering peripheral axons, now termed Schwann cells. He coined the term metabolism for the chemical changes that take place in living tissue, identified the role played by microorganisms in putrefaction, and formulated the basic principles of embryology by observing that the egg is a single cell that eventually develops into a complete organism. His later years were marked by increasing concern with theological issues.
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